Application of chitosan‐entrapped β‐galactosidase in a packed‐bed reactor system

Abstract

ABSTRACT:The model enzyme ␤-galactosidase was entrapped in chitosan gel beads and tested for hydrolytic activity and its potential for application in a packed-bed reactor. The chitosan beads had an enzyme entrapment efficiency of 59% and retained 56% of the enzyme activity of the free enzyme. The Michaelis constant (K m ) was 0.0086 and 0.011 mol/mL for the free and immobilized enzymes, respectively. The maximum velocity of the reaction (V max ) was 285.7 and 55.25 mol mL Ϫ1 min Ϫ1 for the free and immobilized enzymes, respectively. In pH stability tests, the immobilized enzyme exhibited a greater range of pH stability and shifted to include a more acidic pH optimum, compared to that of the free enzyme. A 2.54 ϫ 16.51-cm tubular reactor was constructed to hold 300 mL of chitosan-immobilized enzyme. A full-factorial test design was implemented to test the effect of substrate flow (20 and 100 mL/min), concentration (0.0015 and 0.003M), and repeated use of the test bed on efficiency of the system. Parameters were analyzed using repeated-measures analysis of variance. Flow (p Ͻ 0.05) and concentration (p Ͻ 0.05) significantly affected substrate conversion, as did the interaction progressing from Run 1 to Run 2 on a bed (p Ͻ 0.05). Reactor stability tests indicated that the packed-bed reactor continued to convert substrate for more than 12 h with a minimal reduction in conversion efficiency.

Characteristics of Lactose Hydrolysis by Immobilized β-Galactosidase on Chitosan Bead

“…키토산은 가격이 저렴하고 독성이 없으며 화학적으로 안 정하기 때문에 크로마토그래피, 화학분석, 한외여과 그리고 여러 식품과 산업분야에서 널리 응용되고 있다. 또한 그 동안 키토산을 효소 고정화용 담체로 사용하는 시도가 있었다 [2,5,22]. 키토산 [15].…”

Physico-chemical methods for the chromatographic materials heterogeneity evaluation

“…in the sample liquid [82]. It has been reported that after immobilizing an enzyme to a charged support, there can be a shift in pH optima versus that of free enzyme [83][84][85]. Zeta potential may also be useful in making conclusions about the mechanism of such shifts.…”

“…The tip moves in response to tip-surface interactions, and this movement is measured by focusing a laser beam onto the back of the cantilever and detecting the position of the reflected beam with a photodiode. Different modes of operation can be used [84].…”

Membrane chromatography reactor system for the continuous synthesis of galactosyl-oligosaccharides

“…The enzyme was reported to have stronger hydrolytic activity than transferase activity and produced a high proportion of trisaccharide in the synthetic GOS mixtures [1,2,7]. Some techniques have been developed for immobilization of ß-galactosidase including non-covalent adsorption, covalent binding, entrapment and encapsulation [1][2][3][8][9][10][11]. The newly developed synthetic micro porous membrane adsorbers as chromatographic media are an attractive alternative to traditionally used packed bed chromatography, which has several limitations [12].…”